Metro Line LRT Drainage Projects

Constructing a storm tunnel to mitigate flooding at new LRT station

Project overview

During construction of Edmonton’s new Metro Line LRT, a need arose for a storm tunnel to be constructed at the MacEwan station portal, where the train would return to street level. This tunnel was intended to address storm water flows at MacEwan Station, and designed to provide 1 in 100 year storm event protection to the North LRT tunnel, consequently meeting the design standards for the LRT.

Challenge

In addition to horizontal and vertical alignment requirements, the project needed to meet objectives related to sizing and connections. Poor ground conditions and the project’s location in Edmonton’s bustling downtown intensified its complexity.

Solution

Productivity was key in this complicated project. SMA employed simulation modeling to enhance productivity. Our engineers employed Simphony, modeling software developed at the University of Alberta and specially designed for construction work, with extensive application to tunneling projects. Simulation modeling helped SMA model the optimal process for the tunnel’s construction. SMA also conducted Earned Value Analysis (EVA) to gain a clearer picture into project progress.

Results

The simulation model SMA developed for the portal construction showed that a less than full setup for tunneling was more productive, indicating an agreement between a more sustainable approach and the best fit for the needs of the project. The EVA SMA undertook on both projects gave the City invaluable insight into the actual progress gained. In addition to preventing the flooding of the LRT tunnel, which would have significant safety consequences, the portal drainage project helps reduce damaging infiltration of storm water into other parts of the drainage system.